Fix lint.py will fail for py files when not called from repo root
Fix lint.py will fail for py files when not called from repo root

It's because the file path got from git diff is related to repo root.
So the work dir should be repo root before trying to do pylint.

BUG=https://github.com/otcshare/cameo/issues/31

darktears/crosswalk,jpike88/crosswalk,leonhsl/crosswalk,alex-zhang/crosswalk,darktears/crosswalk,kurli/crosswalk,tedshroyer/crosswalk,DonnaWuDongxia/crosswalk,qjia7/crosswalk,DonnaWuDongxia/crosswalk,chinakids/crosswalk,myroot/crosswalk,jondwillis/crosswalk,RafuCater/crosswalk,chuan9/crosswalk,weiyirong/crosswalk-1,zeropool/crosswalk,dreamsxin/crosswalk,xzhan96/crosswalk,mrunalk/crosswalk,xzhan96/crosswalk,crosswalk-project/crosswalk-efl,hgl888/crosswalk,qjia7/crosswalk,DonnaWuDongxia/crosswalk,DonnaWuDongxia/crosswalk,heke123/crosswalk,wuhengzhi/crosswalk,RafuCater/crosswalk,dreamsxin/crosswalk,hgl888/crosswalk-efl,Bysmyyr/crosswalk,chuan9/crosswalk,XiaosongWei/crosswalk,jondwillis/crosswalk,TheDirtyCalvinist/spacewalk,heke123/crosswalk,jondong/crosswalk,weiyirong/crosswalk-1,DonnaWuDongxia/crosswalk,crosswalk-project/crosswalk-efl,jondwillis/crosswalk,stonegithubs/crosswalk,PeterWangIntel/crosswalk,amaniak/crosswalk,darktears/crosswalk,weiyirong/crosswalk-1,rakuco/crosswalk,stonegithubs/crosswalk,heke123/crosswalk,huningxin/crosswalk,RafuCater/crosswalk,zeropool/crosswalk,hgl888/crosswalk-efl,bestwpw/crosswalk,pozdnyakov/crosswalk,alex-zhang/crosswalk,rakuco/crosswalk,dreamsxin/crosswalk,fujunwei/crosswalk,alex-zhang/crosswalk,marcuspridham/crosswalk,lincsoon/crosswalk,ZhengXinCN/crosswalk,bestwpw/crosswalk,DonnaWuDongxia/crosswalk,myroot/crosswalk,TheDirtyCalvinist/spacewalk,baleboy/crosswalk,Bysmyyr/crosswalk,mrunalk/crosswalk,XiaosongWei/crosswalk,darktears/crosswalk,tomatell/crosswalk,amaniak/crosswalk,minggangw/crosswalk,zliang7/crosswalk,baleboy/crosswalk,Shouqun/crosswalk,hgl888/crosswalk-efl,DonnaWuDongxia/crosswalk,RafuCater/crosswalk,Bysmyyr/crosswalk,pk-sam/crosswalk,baleboy/crosswalk,weiyirong/crosswalk-1,darktears/crosswalk,Pluto-tv/crosswalk,minggangw/crosswalk,hgl888/crosswalk,jondwillis/crosswalk,tomatell/crosswalk,amaniak/crosswalk,xzhan96/crosswalk,Bysmyyr/crosswalk,pk-sam/crosswalk,zeropool/crosswalk,qjia7/crosswalk,tomatell/crosswalk,dreamsxin/crosswalk,tedshroyer/crosswalk,mrunalk/crosswalk,fujunwei/crosswalk,darktears/crosswalk,hgl888/crosswalk-efl,chuan9/crosswalk,PeterWangIntel/crosswalk,crosswalk-project/crosswalk,huningxin/crosswalk,minggangw/crosswalk,zeropool/crosswalk,marcuspridham/crosswalk,jpike88/crosswalk,shaochangbin/crosswalk,chinakids/crosswalk,crosswalk-project/crosswalk,axinging/crosswalk,chuan9/crosswalk,marcuspridham/crosswalk,huningxin/crosswalk,Shouqun/crosswalk,seanlong/crosswalk,amaniak/crosswalk,crosswalk-project/crosswalk-efl,wuhengzhi/crosswalk,lincsoon/crosswalk,TheDirtyCalvinist/spacewalk,wuhengzhi/crosswalk,huningxin/crosswalk,jondwillis/crosswalk,jondong/crosswalk,bestwpw/crosswalk,xzhan96/crosswalk,crosswalk-project/crosswalk,chuan9/crosswalk,xzhan96/crosswalk,fujunwei/crosswalk,jondong/crosswalk,lincsoon/crosswalk,leonhsl/crosswalk,bestwpw/crosswalk,bestwpw/crosswalk,PeterWangIntel/crosswalk,Pluto-tv/crosswalk,zliang7/crosswalk,zliang7/crosswalk,fujunwei/crosswalk,pozdnyakov/crosswalk,jondong/crosswalk,siovene/crosswalk,marcuspridham/crosswalk,kurli/crosswalk,baleboy/crosswalk,seanlong/crosswalk,zeropool/crosswalk,huningxin/crosswalk,Pluto-tv/crosswalk,siovene/crosswalk,minggangw/crosswalk,weiyirong/crosswalk-1,leonhsl/crosswalk,crosswalk-project/crosswalk-efl,Bysmyyr/crosswalk,minggangw/crosswalk,chinakids/crosswalk,Bysmyyr/crosswalk,siovene/crosswalk,rakuco/crosswalk,kurli/crosswalk,zeropool/crosswalk,huningxin/crosswalk,crosswalk-project/crosswalk,wuhengzhi/crosswalk,amaniak/crosswalk,lincsoon/crosswalk,shaochangbin/crosswalk,jondong/crosswalk,zliang7/crosswalk,leonhsl/crosswalk,myroot/crosswalk,zliang7/crosswalk,bestwpw/crosswalk,Pluto-tv/crosswalk,lincsoon/crosswalk,myroot/crosswalk,jondong/crosswalk,jpike88/crosswalk,marcuspridham/crosswalk,hgl888/crosswalk-efl,alex-zhang/crosswalk,jondwillis/crosswalk,tedshroyer/crosswalk,pk-sam/crosswalk,marcuspridham/crosswalk,rakuco/crosswalk,rakuco/crosswalk,hgl888/crosswalk,tedshroyer/crosswalk,hgl888/crosswalk,tomatell/crosswalk,XiaosongWei/crosswalk,bestwpw/crosswalk,tedshroyer/crosswalk,axinging/crosswalk,ZhengXinCN/crosswalk,wuhengzhi/crosswalk,xzhan96/crosswalk,shaochangbin/crosswalk,axinging/crosswalk,marcuspridham/crosswalk,rakuco/crosswalk,lincsoon/crosswalk,axinging/crosswalk,baleboy/crosswalk,siovene/crosswalk,marcuspridham/crosswalk,tomatell/crosswalk,pozdnyakov/crosswalk,leonhsl/crosswalk,crosswalk-project/crosswalk-efl,hgl888/crosswalk-efl,lincsoon/crosswalk,chuan9/crosswalk,leonhsl/crosswalk,RafuCater/crosswalk,minggangw/crosswalk,ZhengXinCN/crosswalk,baleboy/crosswalk,XiaosongWei/crosswalk,fujunwei/crosswalk,dreamsxin/crosswalk,Shouqun/crosswalk,hgl888/crosswalk-efl,siovene/crosswalk,kurli/crosswalk,seanlong/crosswalk,pozdnyakov/crosswalk,tomatell/crosswalk,baleboy/crosswalk,zliang7/crosswalk,jpike88/crosswalk,dreamsxin/crosswalk,RafuCater/crosswalk,axinging/crosswalk,Bysmyyr/crosswalk,PeterWangIntel/crosswalk,jondong/crosswalk,PeterWangIntel/crosswalk,myroot/crosswalk,seanlong/crosswalk,qjia7/crosswalk,xzhan96/crosswalk,heke123/crosswalk,stonegithubs/crosswalk,jondong/crosswalk,chuan9/crosswalk,darktears/crosswalk,chinakids/crosswalk,crosswalk-project/crosswalk,baleboy/crosswalk,axinging/crosswalk,darktears/crosswalk,fujunwei/crosswalk,jondwillis/crosswalk,amaniak/crosswalk,chinakids/crosswalk,jpike88/crosswalk,ZhengXinCN/crosswalk,lincsoon/crosswalk,seanlong/crosswalk,ZhengXinCN/crosswalk,chinakids/crosswalk,ZhengXinCN/crosswalk,TheDirtyCalvinist/spacewalk,stonegithubs/crosswalk,shaochangbin/crosswalk,kurli/crosswalk,stonegithubs/crosswalk,mrunalk/crosswalk,heke123/crosswalk,alex-zhang/crosswalk,fujunwei/crosswalk,pk-sam/crosswalk,Pluto-tv/crosswalk,leonhsl/crosswalk,XiaosongWei/crosswalk,TheDirtyCalvinist/spacewalk,hgl888/crosswalk,weiyirong/crosswalk-1,hgl888/crosswalk,stonegithubs/crosswalk,RafuCater/crosswalk,rakuco/crosswalk,amaniak/crosswalk,alex-zhang/crosswalk,heke123/crosswalk,dreamsxin/crosswalk,siovene/crosswalk,jpike88/crosswalk,weiyirong/crosswalk-1,kurli/crosswalk,stonegithubs/crosswalk,crosswalk-project/crosswalk,crosswalk-project/crosswalk-efl,qjia7/crosswalk,XiaosongWei/crosswalk,minggangw/crosswalk,crosswalk-project/crosswalk,Shouqun/crosswalk,alex-zhang/crosswalk,PeterWangIntel/crosswalk,siovene/crosswalk,tomatell/crosswalk,mrunalk/crosswalk,zliang7/crosswalk,heke123/crosswalk,xzhan96/crosswalk,tedshroyer/crosswalk,heke123/crosswalk,crosswalk-project/crosswalk-efl,shaochangbin/crosswalk,axinging/crosswalk,tedshroyer/crosswalk,jpike88/crosswalk,qjia7/crosswalk,Shouqun/crosswalk,Pluto-tv/crosswalk,rakuco/crosswalk,PeterWangIntel/crosswalk,myroot/crosswalk,XiaosongWei/crosswalk,wuhengzhi/crosswalk,ZhengXinCN/crosswalk,pk-sam/crosswalk,Bysmyyr/crosswalk,mrunalk/crosswalk,hgl888/crosswalk,shaochangbin/crosswalk,pozdnyakov/crosswalk,seanlong/crosswalk,zliang7/crosswalk,minggangw/crosswalk,Pluto-tv/crosswalk,pk-sam/crosswalk,pozdnyakov/crosswalk,pk-sam/crosswalk,zeropool/crosswalk,Shouqun/crosswalk,hgl888/crosswalk,crosswalk-project/crosswalk,TheDirtyCalvinist/spacewalk